Scrolling

Overview

Single screens limited game worlds. Scrolling broke that barrier, letting players explore environments larger than the display. Different platforms handled scrolling differently—some with dedicated hardware, others requiring clever programming. The technique became fundamental to platformers, shooters, and countless other genres.

Fast facts

• Purpose: Display worlds larger than screen.
• Methods: Hardware or software.
• Directions: Horizontal, vertical, multi-directional.
• Challenge: Memory and CPU usage.

Scrolling types

Type	Direction	Example genres
Horizontal	Left/right	Platformers
Vertical	Up/down	Vertical shooters
Multi-directional	Any	Adventure games
Parallax	Multiple layers	Visual depth

Hardware approaches

Platform	Method
NES	Hardware scroll registers
Mega Drive	Multiple scroll planes
SNES	Mode 7, multi-layer
Amiga	Copper list tricks

Software approaches

Technique	Use case
Character scrolling	8-pixel increments
Pixel scrolling	Smooth movement
Colour scroll	Attribute-level
Memory shifting	Brute force

C64 techniques

Method	Result
Hardware scroll	Smooth 0-7 pixel
Screen memory	Character-level
Combined	Full smooth scroll

NES capabilities

Feature	Implementation
Name tables	Four screens
Scroll registers	X/Y position
Mirroring	Memory efficiency
Split scrolling	Status bar trick

Performance considerations

Factor	Impact
Memory bandwidth	Data movement
CPU cycles	Update speed
Screen updates	Vsync timing
Tile updates	Edge drawing

See also

• Parallax Scrolling
• Tile Maps
• Raster Tricks